Duplex brake



Feb. 23, 1943. sw F 2,311,788

DUPLEX BRAKE Filed Aug. 5, 1940 7e I V INVENTOR.

L T fi EDEB/CK SW/FT ATTORNEY.

Patented Feb. 23, 1943 K mm.

,m v BRAKE John Frederick Swift, Detroit, Mich assignor to Hydraulic Brake Company, Detroit, Mich, a corporation of California Application August 5, 1940, Serial No. 851,498 17 Claims." (cm. lac-.152

This invention relates to brakes and more particularly to actuating means therefor.

An object of the invention is to provide a brake including a pair of friction elements or shoes, each operative as forward braking shoes in both directions of braking.

Another object of the invention is to'provlde a combined fluid pressure and mechanical actuating means for the -friction elements or shoes of a brake operative to apply pressure to the toe .of one of the shoes in either direction of braking and to simultaneously apply pressure to the heel of the other shoe.

An important feature of the invention is a brake structure including a combined fluid pressure and mechanical actuating means for activating the friction elements of the brake operative to transmit equalized forces to the toe of one of the shoes and to the heel of the other shoe in both directions of braking.

Other objects of the invention will appear from the following description taken in connection with the accompanying drawing forming a part of this specification, and in which:

Fig. 1 is a verticalsectional view of a brake embodying the invention,

Fig. 2 is a sectional view substantially on line 2-2, Fig. 1, and

Fig. 3 is a modification of the actuating means for the friction element and the associated lever.

Referring to the drawing for more specific details of the invention, l represents a fixed support or backing plate having associated therewith a rotatable drum l2 which may be suitably secured to a wheel, not shown. A pair of correspondinginterchangeable friction elements or shoes it and ii for cooperation with the drum is supported on the backing plate as by steady rests i8.

Each of the shoes includes a web 20 supporting a rim 22 having secured thereto a suitable lining 24 for frictionally engaging the drum. The articulate ends or heels of the shoes normally abut a fixedanchor 26 mounted on the backin'g plate In, and a fluid pressure actuated motor indicated generally at 28, also mounted on the backing plate, has adjusters 30 for the reception of the force applying ends or toes of the shoes.

The adjusters 38 serve to support the shoes in proper spaced relation tothe drum when the brake is at rest. A retractile spring 32 connects the shoes adjacent their articulate ends or heels and corresponding retractile springs 34 and 86 connect the force applying ends or toes of the shoes to the backing plate Ill.

' shoe in both directions of braking.

A pair of corresponding levers 88 and 40 are pivotally mounted on a post or pin 42 rigidly sup- I .48 in oppositely disposed directions so as to norn'ially embrace the anchor 28, and at the extremities of the force transmitting ends they are deformed to provide pockets 48 and 50 for the reception of the articulate ends or heels oi the shoes i4 and i6.

As shown, the motor 28 includes a large chamber 52 and a relatively small chamber 84 arranged in parallel relation to one another and connected as by a port 56. The large chamber 7 has a conventional intake port 58 and opposed pistons 68 reciprocable in the chamber are connected as by thrust pins 62 to the force applying ends or toes of the shoes I l and I6, and correspondingly the chamber 54 has therein opposed pistons 84 connected as by thrust pins 68 to the force applying ends of the levers 88 and 40. Because of the differential in diameters of the chambers 52 and 54 and the function of the levers 38 and 40, equalized forces are applied to the toe of one of the shoes and the heel of the other shoe with equal efiectiveness.

A modification of the invention is illustrated in Fig. 3. In this modification, a conventional motor 68 is employed in lieu of the twin motor 2. Friction elements or shoes 10 corresponding to the shoes it and I6 and levers I2 corresponding to the levers 38 and 80 are connected at their force applying ends by ratio lever M pivotally mounted on thrust pin I6 suitably connected to the pistons of the motor.

In a normal operation, upon delivery of fluid under pressure into the motor 28 or 68, the motor is energized with the resultant movement of the shoes and levers against the resistance of the retractile springs to effectively engage the shoes with the drum and to apply equal force to the toe of one of the shoes and to the heel of the other While this invention has been described in connection with certain specific embodiments, the principle invloved is susceptible of numerous other applications that will readily occur to persons skilled in the art. The invention is, therefore, to be limited only as indicated by the scope of the appended claims.

l-Iaving thus-described the various features r the invention, what I claim as new and desire to secure by Letters Patent is,

1. A brake comprising a fixed support, a drum associated therewith, a pair of shoes mounted on the support for cooperation with the drum, an anchor for the shoes, a pair of levers fulcrumed on the support embracing the shoes and anchor, high pressure means solely for actuating the shoes, and relatively low pressure means for solely actuating the levers.

2. A brake comprising a fixed support, a rotatable drum associated therewith, a pair of shoes mounted on the support for cooperation with the drum, an anchor for the shoes, a pair of levers fulcrumed on the support embracing the shoes and anchor and operative to apply force to the shoes in opposite directions, and a motor including a. high and low pressure means, the high pressure means for solely actuating the shoes and the low pressure means for solely actuating the levers.

3. A brake comprising a fixed support, a rotatable drum associated therewith, a pair of shoes mounted on the support for cooperation with the drum, an anchor between the articulate ends of the shoes, a pair of levers fulcrumed on the support normally engaging the anchor and the articulate ends of the shoes, and means for applying a differential of pressure to the force applying ends of the shoes and levers.

4. A brake comprising a fixed support, a rotatable drum associated therewith, a pair of shoes mounted on the support for cooperation with the drum, an anchor receiving the articulate ends of the shoes, a pair of levers fulcrumed on the support embracing the anchor and the articulate ends of the shoes, and means for applying a differential of pressure to the force-applying ends of the shoes and levers.

5. A brake comprising a fixed support, a rotatable drum associated therewith, a pair of shoes mounted on the support for cooperation with the drum, an anchor on the support receiving the articulate, ends of the shoes, a pair of levers fulcrumed on the support in oppositely disposed relation to one another, one normally at rest upon the anchor and engaging the articulate end of one of the shoes and the other normally at rest, upon the anchor and engaging the articulate end ,of the other shoe, and means for applying a differential of pressure to the force-applying ends of the shoes and levers.

6. A braliepomprising a fixed support, a rotatable drum associated therewith, a pair of shoes mounted on the support for cooperation with the drum, an anchor on the support receiving the articulate ends of the shoes, a pair of corresponding levers fulcrumed on the support transversely of one another at their fulcrum, one normally at rest on the anchor and embracing the articulate end of one shoe and the other normally at rest on the anchor and embracing the articulate end of the other shoe, and fluid pressure means for applying a differential of pressure on the forceapplying ends of the shoes and levers.

7. A brake comprising a fixed support, a rotatable drum associated therewith, a pair of shoes mounted on the support for cooperation with the ,the shoes, levers-fulcrumed on the support having their(force-transrnittirig ends engaging the articulate-ends of the shoes, and a fiuid pressure,

'actua'ted'motor operative to apply a differential drum, an anchor receiving 'the articulate ends of 8. A brake comprising a fixed support, arotatable drum associated therewith, a pair of shoes mounted on the support for cooperation with the drum, an anchor on the support receiving the articulate ends of the shoes, tongs fulcrumed on the support having adjacent ends resting on the anchor and embracing the articulate ends of the shoes, and interconnected fluid pressure means for applying a differential of pressure on the force applying ends of the shoes and tongs.

9. A brake comprising a fixed support, a rotatable drum associated therewith, a pair of shoes mounted on the support for cooperation with the drum, tongs fulcrumed on the support, an anchor for the shoes and tongs said tongs having adjacent ends hooked to embrace the articulate ends of the shoes, high pressure fiuid means for actuating the other ends of the shoes, and relatively low pressure means for actuating the other ends of the tongs. g

10. A brake comprising a fixed support, a rotatable drum associated therewith, a pair of shoes mounted on the support for cooperation with the drum, tongs fulcrumed on the support, an anchor for the articulate ends of the shoes and tongs, high pressure fiuid means for the actuation of the shoes, and a relatively low pressure means for actuation of the tones.

11. A brake comprising a fixed support, a rotatable drum associated therewith, a pair of shoes mounted on the support for cooperation with the drum, an anchor on the support receiving articulate ends of the shoes, tongs fulcrumed on the support having a pair of adjacent ends resting on the anchor and embracing the respective articulate ends of the shoes, an interconnected low and high fluid pressure actuated motor, saidforce applying ends of the shoes connecting the high pressure ends of the motor, and said other pair of adjacent ends of the tongs connecting the low pressure ends of the motor.

12. A brake comprising a fixed support, a rotatable drum associated therewith, a pair of shoes mounted on the support for cooperation with the drum, an anchor on the support receiving the articulate ends of the shoes, a pair of pivoted levers fulcrumed on the support having a pair of adjacent ends resting on the anchor and embracing the articulate ends of the shoes, a fluid pressure actuated motor, and a ratio lever connecting the motor to the force applying ends of the shoes and leversv for the actuation thereof.

13. A brake comprising a fixed support, a rotatable drum associated therewith, a pair of shoes mounted on the support for cooperation with the drum, a pair of levers fulcrumed on the support, an anchor on the support receiving the articulate ends of the shoes and levers, a fiuld pressure actuated motor, and a scale beam interposed between the motor and each of the forceapplying ends of the shoes and levers for transmitting force fronrthe motor to the shoes and levers.

14. A brake comprising a fixed support, a rotatable drum associated therewith, a pair of shoes mounted on the support for cooperation with the drum, a pair of levers fulcrumed on the support, an anchor on the support receiving one set the force-applying ends of the shoes and levers including interconnected motors, one spaced radially inward from the other, on the support.

16. A brake comprising a fixed support, a drum associated therewith, a pair of shoes mounted on the support, an anchor for one end of the shoes, tongs fulcrumed on the support radially inward adjacent the anchor having a pair of adjacent ends resting on the anchor and embracing the anchored ends of the shoes, and interconnected fluid pressure actuated motors spaced radially from one another on the support, the outer motor connected to the other ends of the shoes and the irmer motor connected to the other ends of the tongs.

.17. A brake comprising a fixed support, a rotatable drum associated therewith, a pair of shoes mounted on the support, an anchor on the support receiving the shoes, a pair of levers pivoted on the support adjacent and radially inward of the anchor, and fluid pressure actuated motors on the support adjacent the force-applying ends of the shoes and levers for the actuation thereof, said motor for actuating the levers being radially inward of the motor for actuating the shoes.

J OHN FREDERICK SWIFT. 

